Marine engines are often used in an idle condition for trolling operations, i.e., to slowly propel a marine vessel for a specific purpose such as bait fishing and the like. Quite often, however, the vessel speed at engine idle exceeds a desired speed. Thus, a typical solution is to engage a degree of slip in the engagement of a clutch with a transmission. For example, a hydraulic clutch may be controlled to engage a transmission in a range from full engagement, i.e., zero slip, to no engagement, i.e., full slip.
Typical control systems are initially set with fixed values of a control parameter such as current or voltage to control the amount of slip to a marine transmission during trolling operations. These parameters are defined during initial installation and cannot be changed. However, engine and transmission specifications vary from one machine to the next, so there is no guarantee that the fixed control values are optimal. Furthermore, the engine and transmission operating parameters change over time due to components wearing and changing. As a result, the control system may not be engaging an optimal or even a desired level of slip during the trolling operation.
The present invention is directed to overcoming one or more of the problems as set forth above.